Diffraction grating tool



y 1946. R. D. DONE R DIFFRACTION GRATING TOOL Filed May 25, 1944 MATERIAL TO BE HULED hum W0 n A RB m M W m .L. E NU T U0 A on M MW. w Y E N T A V n 5 m M w m T a llll F m 1| M v v V m w; T w o P M m R E P U 5 MATERIAL BEING nuusn I 4 552: as 38 mo wmEBE 6 zocbwmi 51 Ralph D Donen Patented July 16, 1946 oFFlCE' DIFFRACTION GRATING TOOL Ralph D. Doner, Auburn, Ala.

Application May 23,

5 Claims.

My invention relates to the art of producing diffraction gratings and it particularly has for an object to provide a tool for the rapid production of an iridescent effect on commercial articles or on stock that can then be punched out and cemented onto such articles.

Other objects will in part be obvious and in part be pointed out hereinafter.

To the attainment of the aforesaid objects and ends the invention also resides in those novel details of construction, combination and arthe diffraction grating tool.

Fig. 5 is a diagrammatic view explaining the action of the tool and the type of cut it is intendedtoproduce.

Fig. 6 is an enlarged detail elevation of the chisel at the completion of one of the cuts.

In the drawing, E represents a socketed body' having a threaded stem e. In the socket of the body is placed a diamond (preferably) cutter, which is held in place by suitable cement E. Two plane surfaces A and B are ground and lappedto form an accurate edge L, with the dihedral angle approximately 90 to 115. Two other faces and D may be'formed to clear or define the ends of the edge L.

The chisel is mounted, as shown in Fig. 4, on a bracket F that is in turn mounted at H on the arm G. The arm G is pivoted at P on a suitable support 11, indicated in dotted lines in Fig. 4.

The bracket F is mounted so as to be adjustable about the axis of the portion H and clamped in any desired adjusted position. or it can be left free to turn into a position such that the edge L makes'a uniform contact with the surface being worked. Y t

The pivot P permits movement of the arm G v} in a vertical direction only, and it may be a short shaft with cone bearings on each end or even split-sleeve bearings allowing clamping in position as may be found desirable.

V indicates a vibrating mechanism, hereinafter again referred to.

1944, Serial No. 536,941

The conventional technique for producing a difi'ractiongrating requires at least two'steps: 1the preparation of the surface by grinding and polishing to mirror-like smoothness; 2''-the 5 ruling with a diamond point of individual grooves or furrows to form the non-reflecting or scattering strips, and leaving equally spaced reflecting strips in between these. 1

A few modifications of this process have been used, such as: ruling specially shaped grooves that reflect instead of scatter light; reproduction of master gratings by molding or stamping; and using tools with many ruling points, such as are disclosed in my Patent No. 2,102,521, and the like. 1 1.

The tool of my present invention and its operation differ from the conventional in several new and radical features:

1. Instead of a point or many points, it involves a cutting edge or chisel, preferably adiamond chisel.

2. Instead of ruling furrows longitudinally, it forms the corrugations by a single transverse or crosswise stroke. 7

3. Instead of the furrows being the non-reflecting areas, the surface is machined completely .into staggered or echeloned reflecting areas with no scattering areasintervening. I

4. The surface need not be particularly smooth, 30 since the tool cuts away all of the old surface to a finite depth in forming the shingle-like echelon planes.

5. The tool may be used on a preparatory cut to machine one smooth continuous mirror- 35 like plane; then retrace its path to form-the echelon planes. Y

6. The path of one stroke of the tool is the full Width of the cutting edge, say A or% inch,-

instead of say 0.0001 inch, and can out say 2500 or more microscopic echelon planes per second; hence the speed is stepped up many hundredfold.

' The action of this tool requires a pulsating downward pressure against the material being ruled. This may be produced by combining a I, constant pressure sufficient to cause the tool to cut to the desired depth and a vibratory oralter- .nating pressure of suificient intensity and of such frequency as to cause the effect described below. In Fig. 4 :the part shown at V .is .the vibrating mechanism. It may be an electromagnet actuated by A. C. or interrupted D. 0., an air-driven reed, or any conventional mechanism. In fact, the vibratory pressure may be applied, instead, to the surface directly. Just so the resulting contact pressu 1 components are separately adjustable.

Fig. explains the action of thetool, and the type of cut it is intended to produce. The tool I is lowered (pivoting at P) onto the surface in 3 such'a position that edge L (Fig. 4) makes tangential contact. The angle be tween face B and 1 A to make an angle of say"50 to"80flwith the 1 surface on the other side, or as shown, to the right. Now, if the tool is given a uniform motion- 5 toward the right or, preferably, the surface-is moved to the left, and only a constant contact pressure is maintained, a smooth cutwill result." 'Adding the vibratory pressure, however, will modify the form of cut as follows: say the pulsating pressure has reached stage R, Fig. 5, andthe 2. In a tool of the character described: an arm pivotally mounted for movement in a vertical direction; a bracket carried by said arm; a chisel member carried by said bracket, said chisel member having two plane faces disposed at an angle to one another to define a straight cutting edge' extending transversely to the length of said arm; and means for imparting a pulsating downward the surface is adjusted ,des r i,- 1c. c ab y i .7 re sur 1 sai end, io lf PQF the neighborheodiof 10 to causes face 10 scribed. H

" 3. In a tool of the character described: a chisel member comprising a holder, a diamond mounted ""in the holder, said diamond and holder having two pla-ne'surfaces meeting in a straight edge and forming an angle of 90 to 115, said diamond having two other plane surfaces at 90 from the .iirst two plane surfaces to define between them a predetermined length of said straight edge; a

"pivoted arm movable only in a. direction normal 20 to the plane of the surface to be worked on; a bracket mounted on: said Farm; 'm'ea-nsyt'm-mount said chisel member on' said bracket withitsgraxis inclined so 535 to'locate one-of-gthe first two; mentioned plane surfacesto make ananglezoffrom 10 =to 20 with the face of the materiaLbe-ing worked on; and means to impart a;pulsatin pressure of the chisel member:againstandin a direction towardsaid material. M j

14. .In a tool of the .rcharacterdescribed-:aohisel member comprising a holder adia-mond mounted in the holder, said diamond and -ho'ldere having two plane surfaces-.meeting in agstraight; edge 5 and formingian angleof 59.0 .i to; 1 15?; said rlianiond a n w he jp esurfaces atri ntifromt "first QtWO plane .--s-ur;f aces to define: between them a predetermined length of said straight:ed'ge;.-'a pivotedarm movable only inya direction.I. o-rmal to the plane of the surface to be workedgon ia bracket mounted on said; arm; :means toglmount said chisel member on said bracket with its :laxis inclined so as to locate one of the-first twdmendepth of cut corresponding to it is at R. Up to this'p'oint; face Ahasbeen'bearingthe support :of "the pressure, Nowii as .therpressure increases rflzto .phasefis; thetoola-must sink-deeper into the i-isu-rface'in order to give Apabroa'der bearingjarea.

:But: it; cannot sink faster. than theinclination M2 :face:.iB :will .allow,.since B presents .a uniformly 1 increasing. bearing area .asmthe: motion proceeds. Hence the cut will take the; path 3Rv .to 'S, where V 1S; determined by. the pressurelhaving .diminshed to,.a=:point .where :face. .Azcan' again fully; srsupport the pressure. As the pressure further diminishes'fromstages S- :tdfly. the toolawill rise probably ,on ia: sheer :plane) 'ito ,.'1,' .Th11s:is ;.*achieved; relatively 'long,:.but gentlyisloped fpl'anes R'S, T'U, etc., alternating with short butqsteep l :irises:'Q'-R',.SfT?; etc.f. r. i Aatypical iset' 'ofiadjustments isito.,maker;about 10,000 of these echeloned planeszperj:linearinch, ...:ti1td.-S2.Y..1D1With the horizontal, andt-heabrupt .'.rises atileast.45.':' "puts the echeloned planes 2 3 out of co-planar position by a veryfiewwave- 2 lengthsiof I .1ight..-necessary for; producing igood ...=dififracti'onj oflincident' light; highwas 190% .of

the surface can be made opticallysactiye, instead 7 hitheconve'ntional :Furtherm*ore,;more ofhezulight energyjsiconcentratedin oneorderiof .5 .spectrum',;- especially. wheni thejncidentdightlis. V v l nearly m l tojthe'iechfibned planes, 5. In a;tool ofthe'characteredescribed, aichisel l. .iihis,.tool.'lends itselfreadilymocompounding member comprising a holdergaidiamond'mounted -;ofiridescentz.effects, for. the pitchiof the Vibration 2 0 in the, holder, said.zdiarrrondyand holder; having ""zmaybema-ltered While.theztooliismctive, oTijlhe wo p nes rfa s meetinglinca strai ht v ds I rate of motion may be varied,. thu's;;producing and for-mingcan ang :O 09 0 iv a l ndifferent spacingsyiand 'consequently' :flifierent optical properties aregiventto': the surface at; will.

material that? cuts 'smoothly-maysbeoperated 5;; upon; metals are the preferred materialibutffair aresults .;-ar ...obtainable on some rpia'stics. -:Only him-ts: ofthe surface .asn are; prncessmggach bracket mountedjon;saidarmgjimeansctormount .cut' being La band 'thei'width of .thQQChiSelEedge, .isaid, chisel member: onrsaidgbracketwith itsi'axis u. .'t.;From1the foregoing description; taken'in. chug-6Q ainclin'ed so as'towlocateionei Of the Ifirstttwo'inen- .4nection with the accompanying. drawingyitiis flned plaiie surfa-ces to' make-:aniangletofrfrom thought that the construction, and operationaof lQ 0 20 withtherfaceof the'inaterim b n 1 .myzne and.improved...tool..willbe nlear tqthose worked on;;iand;means toimpart apulsatingipresg.-.=skilled..in the art. i 1 i c isu-reof the chiselmemberiagainsteanddnxa direc- ,-.WhatIc1ai1'n.is-: V; i .g. tif itionftoward'said materiaksaidlastnamiedrmeans 11.; Ina toollofthe:charactercdescribedz a hori vincludi tsa yibratingpmechanismi; -'zontal ly; pivoted armgi-a'uchi'sel memberzmounted "csai-dearmn I L r on said. arm to engage rthe'; work; sand. means ito apply-a pulsating downward pressureiof the' chisel 7 10 to '20? with; the face ;of the :mat-erial-being worked on; and meanstoimpart: a pulsating, pressure of the chisel memberaagainst and. in 2.:dl160- tion towardsaidmaterial, said .lastnamed means including a vibrating mechanism..: p l

first two. plane surfaces 'toiidefine abetween-..them a predetermined length of isaidstraightcedge; a pivoted; arm movableaorrlysinwa directionznormal tosthe plane 'of .the surface-.to; be WQI'kedliOIljJ a fem" (against thematerialibeingicut.

j -.tioned plane surfaces to 'rnake,;an;:an;g1e ofifrom V havingtwo other planessurfacesat=fl0ifromithe mounted: on 

